Plant cell walls are affected by many biotic and abiotic stress conditions. The aim of this study is to determine the effects of 24-Epibrassinolide (EBL) on some cell wall-related genes in root tissue of five- and ten-week-old Arabidopsis thaliana plants exposed to boron (B) deficiency (0 mu M) or toxicity (3000( )mu M) at the transcriptional level. Expressions of the genes that encode cellulose synthase (CESA1, CESA4, CESA6 and CESA8), cellulose synthase-like (CSLBS), expansin (EXPAS, EXPA8 and EXPA14) and cell wall protein (SEB1) decreased under conditions of B deficiency and toxicity. EBL treatments, in general, led the expressions of these genes to reduce significantly. Expressions of xyloglucan endotransglucosylase/hydrolase genes (XTH21 and XTH23) changed only under conditions of B toxicity. Boron stress and/or EBL treatments caused different responses in expression of pectin methylesterase (PME2 and PME41) genes. As a result of B stress, the expression levels of investigated genes changed more in roots of five-weekold plants than in roots of ten-week-old plants. Results of the present study include new findings that support the ability of BRs to increase molecular aspects of tolerance to stress in plants.